The present invention relates to the art of vehicle anti-theft systems and, more particularly, to a system comprised of separate mechanical and electrical security devices having a feature of co-dependency with respect to the use thereof and electrical security devices capable of remaining in an armed mode in response to tampering.
Vehicle anti-theft devices which are mechanically operable to restrain rotation of the vehicle steering wheel are of course well know and such mechanical devices are shown, for example, in U.S. Pat. Nos. 4,738,127 to Johnson and 4,961,331 to Winner, the disclosures of which are incorporated by reference herein for background information. These devices include a pair of attachment components in the form of hooks, each on a different one of a pair of telescopically interengaged members of the device, whereby the hooks are adapted to be relatively displaced between extended and retracted positions relative to one another and which positions correspond, respectively, to mounted and dismounted positions for the device. In use of the Johnson device, the hooks engage diametrically opposed portions of the steering wheel rim of a vehicle and the device includes an arm extending radially outwardly of the rim to preclude rotation of the steering wheel by engagement of the arm with the interior of the vehicle or the operator thereof. In use of the Winner device, one hook engages the steering wheel rim and the other engages a foot pedal lever on the floor of the vehicle, whereby both rotation of the steering wheel and depression of the foot pedal are restrained so as to preclude unauthorized operation of the vehicle. In each device, a key operated lock mechanism is provided for locking the hooks against relative displacement when in the mounted position of the device and for unlocking the hooks for relative displacement to enable dismounting of the device from its use position.
While mechanically operable vehicle anti-theft devices such as those shown in the Johnson and Winner patents are extremely effective anti-theft devices, vehicle operators often desire to optimize protection of their vehicles against theft by using such a mechanical device in conjunction with an electrically operated security device either installed in the vehicle at the time of manufacturer and integrated with the electrical system of the vehicle, or installed in the vehicle subsequent to manufacture thereof. Arming and disarming of such devices is generally achieved through the use a key operated switch arrangement located outside or inside the vehicle, or through an encoded signal from a remote transmitter as shown in U.S. Pat. No. 4,958,084 to Carlo et al, the disclosure of which is also incorporated herein by reference. Such devices may, for example, provide the desired anti-theft deterrent when armed by issuing a visible or audible alarm in response to an attempt to enter the vehicle or, as disclosed in Carlo et al, by inhibiting operation of a portion or portions of the electrical system in the vehicle such as the ignition system so as to preclude starting of the vehicle other than by an authorized user.
While it is desirable to combine mechanical and electrical anti-theft devices of the foregoing character to provide a vehicle owner with better protection against theft, use of the two devices requires two keys, or a key and a transmitter, one unique to each device. Thus, one or the other of the devices may not be used by a vehicle owner because of the inconvenience of having to carry two extra keys, or an extra key and a transmitter, in conjunction with use of the vehicle and the inconvenience of having to locate one of the keys or the transmitter to arm or disarm the electrical security device and having to locate the key for mounting or dismounting the mechanical device. If both devices are not used, or should a vehicle owner opt not to use a second device, the advantage of an added deterrent to theft of the vehicle can not be obtained. Further, in connection with electrical anti-theft devices, thieves are quite adapt at cutting wires or otherwise disabling such devices, whereby the deterrent effect thereof is substantially reduced or totally lost.